Chris, if I read Sagawa's "Tomei na Chikara", if I'm not mistaken, there's a part that says Takeda Sokaku Dai-sensei learned martial arts from Saigo Tanomo. Some people said Saigo's the adviser, but hey, that time, "advisor" is really your tutor, right?

You should also note that Sagawa was extremely skeptical about any real connection between Saigo Tanomo and Sokaku Takeda in terms of martial transmission.